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So I am trying to create a application that simulates a online video store. I have created a database on Workbench and I am trying to create a if statement that checks if the user input matches those on the emails and passwords on the database. But I either get a error about the connection or about the driver. Hoping someone can help me out, thanks!

Here is the Java code

public static void main(String[] args) throws SQLException, ClassNotFoundException
{       
            Class.forName("com.mysql.jdbc.Driver");
            Scanner input = new Scanner(System.in);
            String answer = "";
            String sql = "";
            String email = "";
            String password = "";

            Connection myConn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql?zeroDateTimeBehavior=convertToNull [root on Default schema]", "<username>", "<password>");                        
            Statement myStmt = myConn.prepareStatement(sql);
            ResultSet rs;

            while(!answer.equals("n") || !answer.equals("y") )
            {
                System.out.print("Do you have an account? (Y/N) : ");
                answer = input.nextLine();

                if(answer.toLowerCase().equals("n"))
                {
                    System.out.println("Please enter the email and password for your new account.");
                    System.out.print("Email: ");
                    email = input.nextLine();
                    System.out.print("Password: ");
                    password = input.nextLine();
                    sql = "insert into accounts "
        + " (UserEmail, UserPassword)" + " values (?, ?)";

                    myStmt.executeUpdate(sql);


                }
                else if(answer.toLowerCase().equals("y"))
                {
                    System.out.print("\nEmail: ");
                    email = input.nextLine();
                    System.out.print("\nPassword:");
                    password = input.nextLine();
                    rs = myStmt.executeQuery(sql);
                    if(!rs.absolute(1))
                    {
                        System.out.println("You do not have an account. Please create one.");
                        continue;
                    }
                }
                else{
                    System.out.println("Invalid input. Please try again.");
                    continue;
                }
            }

Here is my SQL script

create database users;
use users;
create Table Accounts(
UserEamil Char(20) NOT NULL ,
UserPassword Char(20) NOT NULL
);

Here is my error: Exception in thread "main" java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

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2
  • 1
    please post the error you got too Commented Aug 4, 2017 at 1:03
  • I added it. And if I comment out the class.forname line, I get this error: Exception in thread "main" java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/mysql?zeroDateTimeBehavior=convertToNull [root on Default schema] Commented Aug 4, 2017 at 1:12

2 Answers 2

Reset to default
0

This code is not going to work as the values have not been set

sql = "insert into accounts "
    + " (UserEmail, UserPassword)" + " values (?, ?)";

myStmt.executeUpdate(sql);

what you should do is create a PreparedStatement using the sql and then call setString for each paramater like

sql = "insert into accounts "
    + " (UserEmail, UserPassword)" + " values (?, ?)";
Statement myStmt = myConn.prepareStatement(sql);
myStmt.setString (1, email);
myStmt.setString (2, password);

myStmt.executeUpdate ();

note

Currently at the top of your code you have

        Connection myConn = DriverManager.getConnection("....");                        
        Statement myStmt = myConn.prepareStatement(sql);

but the value of sql at this time is an empty string - it will not work

note2

Consult this answer for how to set your connection String correctly

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4 Comments

Thank you, this makes much more sense. Besides my driver problems, do you have any other suggestions?
yes, while(!answer.equals("n") || !answer.equals("y") ) should use && not ||
Got my driver working, but now I get this error: Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'UserEmail' in 'field list' Any thoughts?
yes it means that the column does not exist in the db table
0

Have you downloaded the mysql jdbc driver? You should be able to fix it by adding the classpath:

C:\test>java -cp c:\test\mysql-connector-java-5.1.8-bin.jar;c:\test JDBCExample

Taken from: https://www.mkyong.com/jdbc/how-to-connect-to-mysql-with-jdbc-driver-java/

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3 Comments

ClassNotFoundException generally means Java could not find the specified class, and you need to provide the class or the library in the classpath, my advice is to play around with your classpath settings, ensure you are referencing it correctly.
I have the whole mysql-connector folder in my project folder but it is not in my src folder. Should I put it in there or should I change the " Class.forName("com.mysql.jdbc.Driver")" line?
How do I add the .jar file to my projects classpath?

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